Electromagnetic device



Patented Aug. 11, 1 931 UNITED/STATES PATENT OFFICE PAUL I. ZIMMERMAN, OF CHIOAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC GOM- RANY, INCORPORATED, OF, NEW YORK, N. Y., A CORPORATION OIJNEW YORK ELECTROMAGNETIC DEVICE No Ilrawing.

This invention relates to electromagnetic devices, and more particularly to magnetic cores used in connection with inductance coils employed in carrier current communi- 5 cation systems. 1

Electrical inductance coils used in carrier current communication are usually provided with cores-having a comparatively low permeability,'such cores being prepared by mixing fine particles of a material of high magnetic permeability with an inert binder, such as kaolin and then compressing the material into the desired form, thus compacting the materials together to form a rigid and'substantially homogeneous core part;

An object of this invention is to provide a magnetic core or other electromagnetic device having improved mechanical properties and satisfactory magnetic .properties.

comprises the use of an improved insulating material or binder consisting of zirconium silicate or similar material, either alone or a combined with another material or materials such as kaolin, whereby the mechanical properties of the core are materially im' proved and the electrical properties are of the proper value. Y

The above and otherobjects of the invention will become apparent from the following description, wherein a preferred embodiment of the invention is specifically disclosed. a

In the manufacture of cores'in accordance with the present invention, one of the materials used is' permalloy, which is an alloyof iron and nickel in the desired proportions depending upon the properties required, a ratio of 78% parts nickel to 21 parts iron 40 being satisfactory for most purposes. This material is used in the form of a dust or powder, preferably of such fineness that it will pass a' SOD-mesh screen, and-is first treated with any satisfactory known insulating composition, preferably one having substantially the composition of that disclosed in Patent 1,669,643, granted May 15, 1928 to J. W. Andrews et al. The insulating com ositioi'i is applied to the permalloy dust in t e manner described in the above men- In general terms, the present invention Application filed September 13, 1930. Serial No. 481,811.

.tioned patent to Andrews et al, the urpose being to cause thecomposition to orm an insulating coating over the individual particles of permalloy, after which the mixture is dried. To the resulting material is then added about nine parts'of. a binder consisting preferably of a dry mixture of zirconium silicate and kaolin in the ratio of about three parts by weight of zirconium silicate to one part kaolin although various other ratios may be user as pointed outbelow. The entire mass is then thoroughly mixed together, and is then compressed into rings or other suitable shapes, which are heat treated to give the desired magnetic qualities, after which the rings are ready to be assembled into inductance coils.

It has been found that cores and other parts formed in the manner above described have exceptionally good mechanical properties, since they are not subject to cracking, and that their magnetic and electrical qua ities are especially satisfactory.

While the invention has been described with reference to certain'ingredients used in certain specified proportions, it will, be

nnderstood that both the ingredients and the proportions thereof may be considerably varied. Thus, other inert binders than kaolin may be employed, and other materials such as cupric oxide and magnesite may be substituted for the zirconium silicate. It

is also within the contemplation of the present invention to omit the kaolin, the binder in such case being composed merely of Znconium silicate or of the other materials above mentioned. The invention is therefore not limited to the specific details above disclosed, but is limited only by the terms of the following claims. 7

What is claimed is:

1. As a new article of manufacture particles of a magnetic material, and a mate rial COIltiLlIllIlgZlICOIllllIll silicate separating the particles.

2. An electromagnetic device comprising particles of a magnetic material bound together by a mixture of zirconium silicate and kaol1n.

. 3. An electromagnetic device comprising finely divided particles of a magnetic material insulated from each other by an insulating substance and bound together by a substance containing zirconium silicate.

5 4. An electromagnetic device comprising finely divided particles of a nickel-iron alloy coated with an insulating substance and bound together by a mixture of zirconium silicate and kaolin. r

- 5. An electromagnetic device comprising particles of a magnetic metal having an insulating coating thereon and bound together by a material containing zirconium silicate,

the coated particles and the material being compacted together by pressure.

6. A core for inductance coils comprising finely divided particles of a nickel-iron al- J loy coated with an insulating material and bound together by a mixture of zirconium silicate and kaolin in the ratio 'ofsubstantially three parts by weight of zirconium silicate to one part of kaolin.

7; A core for inductance coils consisting v of finely divided particles of a nickel-iron alloy coated with an insulating material and bound together by a mixture of zirconium 7 silicate and kaolin, said particles'and mixture being compacted into the desired form under high pressure. 8. An electromagnetic device comprising particlesv of a magnetic material bound together by a material selected from the group consisting of zirconium silicate, cupric oxide, and magnesite. u 9. An electromagnetic device comprising particles of a magnetic material bound together by zirconium silicate.

10. An electromagnetic device comprising particles of a magnetic material bound to- 40 gether by cupric oxide.

11. An electromagnetic device comprising particles of a magnetic material bound together by magnesite.

. In witness whereof, I hereunto subscribe my name this 27th day of August A. D.,

PAUL P. ZIMMERMAN. 

